title: In vitro anti-caries effect of fluoridated hydroxyapatite-coated preformed metal crowns.
abstract: OBJECTIVE
  To synthesise fluoridated hydroxyapatite (FA) crystals directly on preformed metal crowns (PMCs) and evaluate the anti-cariogenic properties in an in vitro model.
  
  
  METHODS
  FA crystals were grown on etched PMCs and stainless steel discs and characterised by SEM. FA-coated discs allowed fluoride release to be assessed from a known surface area of FA crystals. Discs were divided into four groups (n = 6/group) and exposed to solutions at pH 4-7. Fluoride levels in solution were measured after each exposure. Twelve FA-coated and 12 non-coated PMCs were cemented onto human molars using glass ionomer (GI) or unfilled resin, making four groups of six teeth; FA-coated + GI, FA-coated + resin; non-coated + GI and non-coated + resin. Teeth were exposed to acidified gelatin (pH = 4.3) for 9 weeks.
  
  
  RESULTS
  SEM showed FA crystal growth on interior and exterior of the crowns. Average fluoride release from FA-coated discs was 0.16 mg/L/cm² at pH < 5.0. Teeth were sectioned through the lesion. Polarised microscopic examination revealed significantly smaller lesions in FA-coated crown groups compared to non-coated crown groups.
  
  
  CONCLUSIONS
  FA-coated PMCs demonstrated carious lesion preventing effects, i.e. fluoride release and reduction of demineralisation at crown/tooth interface. FA-coated crowns could be an aesthetic, inexpensive and caries preventive alternative in clinical dentistry.
authors.affiliation: Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, Room 2391, University of Michigan , 1011 N University Ave, Ann Arbor, MI, 48109-1078, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Clark
authors.forename: A
authors.initials: A
authors.lastname: Czajka-Jakubowska
authors.forename: C
authors.initials: C
authors.lastname: Rick
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Chang
authors.forename: B H
authors.initials: BH
authors.lastname: Clarkson
mesh_terms: D003442:Crowns; D003731:Dental Caries / Q000517:prevention & control; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008963:Molar; D013193:Stainless Steel / Q000737:chemistry
chemical_list: D005899:Glass Ionomer Cements; D013193:Stainless Steel